There is actually a lot of interesting stuff in the Judahite genealogies of ch. 4 of 1 Chronicles. I gave two examples of obvious toponyms presented as PNs (Ir-Nahash and Ge Harashim), but there are many others, such as Bethlehem, Tekoa, and Beth-Rapha, and if you compare the names in this section with the list of conquered Canaanite cities in the tribal allotment of Judah in Joshua 15, you will find that many are identical (such as Zorah in Joshua 15:22 and 1 Chronicles 4:2, Ethnan/Ithnan in Joshua 15:23 and 1 Chronicles 4:7, Ziph in Joshua 15:24, 55 and 1 Chronicles 4:16, Eshtemoa in Joshua 15:50 and 1 Chronicles 4:17, Gedor in Joshua 15:58 and 1 Chronicles 4:17, Sokoh in Joshua 15:35, 48 and 1 Chronicles 4:17, Zanoah in Joshua 15:34, 56 and 1 Chronicles 4:17, Keilah in Joshua 15:44 and 1 Chronicles 4:19, and Mareshah in Joshua 15:44 and 1 Chronicles 4:21). So what is Canaanite in one tradition is Judahite in another.
There are also interesting connections with the patriarchal traditions in Genesis. In v. 21, the "men of Cozeba" and "Laadah the father of Mareshah" are mentioned as among the sons of Shelah, the son of Judah (cf. Joshua 15:44 where Mareshah and Achzib are mentioned together as towns in Judah), and in Genesis 38:5 we read that Judah married " the daughter of a Canaanite man named Shua" and she gave birth to Shelah at Chezib. The two names are probably related and it is interesting that the tradition makes the descendents of Shelah have Canaanite ancestry; this is probably a historical memory of the fact that the people who were Canaanites in the LBA became Israelites/Judahites in the IA (a change in political and ethnic identity). Shua, moreover, has an analogue in the Shuhah of v. 11, who is explicitly designated as a Kenite (i.e. of Edomite or Midianite origin). There is also the problem of the Kenizzites, affiliated with the Kenites in Genesis 15:19. The reference to "Eshlon the Kenizzite" in v. 12 (LXX) directly precedes the listing of the sons of Kenaz in v. 13, who is given a Judahite genealogy. The connection between the two is clear from such passages as Numbers 32:12, Joshua 14:5, 14 where "Caleb son of Jephunneh" (mentioned in 1 Chronicles 4:15) is termed a Kenizzite, whereas for the Chronicler (and elsewhere) Caleb son of Jephunneh was mentioned directly after the sons of Kenaz but not directly linked to him (whereas Othniel, brother of Caleb in Joshua, is stated to be the son of Kenaz). And in addition to the pre-Edomite Kenizzites in Genesis 15:19, there was also an Edomite Kenaz. The sons of Eliphaz the firstborn of Esau/Edom were Teman, Omar, Zepho, Kenaz, Korah, Gatam, and Amalek (Genesis 36:15). This includes the eponym Amalek for the Amalekites, just as Kenaz is the eponym for the Kenizzites. "Teman" connects directly with the Judahite "Temani", the son of Ashhur through Naarah (1 Chronicles 4:6); Temani is a gentilic form, making him the ancestor of the Temanite people (cf. Job 2:11 where Eliphaz is described as a Temanite). "Zepho" is cognate to the Ziph and Ziphah in 1 Chronicles 4:16 and notice that Zepho is affiliated with Korah. In 1 Chronicles 2:42-43, we read that Korah, Mareshah, and Ziph are clans of Caleb "the brother of Jerahmeel".
The detailed asides in ch. 4 of 1 Chronicles also give additional information. In addition to the asides about Ir-Nahash and Ge Harashim, it is stated that Mered son of Ezrah married Bithiah, daughter of Pharaoh, which gave birth to Miriam, Shammai, and Ishbah father of Eshtemoa (v. 17-18). This clearly attests intermarriage between Judahites and foreign elements in the population; in this case, Egyptian (the name Miriam also is consistent with an Egyptian theme). The next verse (v. 19) moreover refers to "Eshtemoa the Maakathite", and this is another Canaanite ethnonym, cf. Joshua 13:13: " But the Israelites did not drive out the people of Geshur and Maakah, so they continue to live among the Israelites to this day" (compare Deuteronomy 3:14). And Maakah in 1 Chronicles 2:48 is named as the (Canaanite?) concubine of Caleb the brother of Jerahmeel. So Eshtemoa, while a Maakathite (a Canaanite according to Joshua), is reckoned as a Judahite by the Chronicler. Finally, we have this material at the end of the Judahite genealogy:
1 Chronicles 4:21-23: "The sons of Shelah son of Judah: Er the father of Lekah, Laadah the father of Mareshah and the clans of the linen workers at Beth Ashbea, Jokim, the men of Kozeba, and Joash and Saraph, who ruled in Moab and Jashubi Lehem. (These records are from ancient times.) They were the potters who lived at Netaim and Gederah; they stayed there and worked for the king."
First of all, we have two more examples of professional guilds reckoned as clans: "the clans of the linen workers at Beth Ashbea" and the "potters who lived at Netaim and Gederah" reckoned among the Shelah clans of Judah (which as mentioned above have a Canaanite origin). And notice too that Jokim, Joash, Saraph, and the "men of Cozeba" are said to have "ruled in Moab"; supposed Judahites here are designated as Moabite rulers (probably not kings but possibly governors). So this points to some fluidity between the peoples of Moab and Judah.